Device and Method for Dropping Fragile Products

ABSTRACT

The invention concerns a device ( 10 ) for dropping fragile products ( 5 ) comprising: —a storage means ( 4 ) for storing said products, comprising a discharge means ( 4   a ) for discharging said products, —a means for distributing the fragile products comprising at least one cavity ( 1   a,    1   b ) provided in the surface of a support ( 2 ), the support being capable of assuming at least two positions, a first position in which the at least one cavity is located opposite and at a distance from said discharge means and can be filled with fragile products, and a second position in which said cavity is spaced apart from said discharge means and can be emptied, said device further comprising a flexible means ( 3 ) for bringing the discharge means with the at least one cavity into communication in order to fill said cavity with fragile products.

The invention concerns a device for dropping in the atmosphere fragileproducts such as insects without damaging them and in controlledquantities. The invention also relates to a method for dropping, whichimplements the device and a transport means equipped with such a device.

The dropping of insects sterilised by irradiation or geneticallymodified in a natural environment has become a major way to fightcertain diseases: malaria and arboviruses (Chikungunya, Dengue, Zika)with mosquitoes, African trypanosomiasis (sleeping sickness in humansand Nagana in animals) with the tsetse fly.

The dropped insects have been sterilised by irradiation or geneticallymodified so that their offspring is not viable. They come intocompetition with natural insects and contribute to their eradication.This enables to avoid the large-scale diffusion of pesticides. In otherapplications, parasitoids are dropped, for example Trichogrammae. Theseparasitoids feed off the larvae of harmful insects.

The drop must be performed in precisely-determined quantities as thedevice is intended for dropping products that are expected to have aneffect on the environment, and the drop must enable to achieve ameasurable effect in a predefined area.

Several devices for dropping fragile products in a natural environmentand in precisely-measured quantities are known. One of the ways consistsof using a worm drive. This system presents the disadvantage of damaginga large proportion of the fragile products. Devices using a vibrationtable are also known. The operation of these devices is disrupted by thevibration of the transport means (light aircraft) in which they areloaded on, and therefore lose the accuracy thereof. Finally, devicesusing a belt conveyor are also known, but they cannot be used to dropsmall quantities of insects and they injure the insects (see for exampleMXNL05000060).

For this purpose, the invention proposes a device for the dropping offragile products comprising:

-   -   a storage means of said products, comprising a discharge means        of said products,    -   a distribution means of the fragile products comprising at least        one cavity provided at the surface of a support, the support        being capable of taking at least two positions, a first position        wherein the at least one cavity is located facing and at a        distance of said discharge means and can be filled with fragile        products, and a second position wherein said cavity is spaced        apart from said discharge means and can be emptied,    -   said device further comprising a flexible means of bringing the        discharge means into communication with at least one cavity in        order to fill said cavity with fragile products.

The device comprises mainly a means to store the fragile products to bedropped, such as a hopper, and a means to distribute the fragileproducts. The hopper conventionally comprises a discharge means, such asa narrowing and an orifice in the lower section during operations.

The distribution means comprises a support with cavities on the surface,i.e. open cavities that can be filled and then emptied. The support canbe animated with a motion, such as rotation or back-and-forth, as willbe described below, enabling, in the first position, to present a cavityfacing the orifice of the discharge means of the hopper and, in thesecond position, to move this cavity away from the hopper. In the firstposition, the cavity is filled, by gravity, with fragile products, andin the second position it is emptied.

This arrangement, in itself, enables to control the dropping of fragileproducts, since the volume of the cavities and the frequency at whichthey present themselves in front of the orifice of the hopper can beadjusted by the user.

The difficulty consists of, on the one hand, avoiding the dispersion ofthe fragile products in the first position of the support, when theproducts pass from the hopper into the cavity, and on the other hand,avoiding damages to the fragile products when passing from the first tothe second position of the support.

For this purpose:

-   -   on the one hand, the support is located at a distance from the        discharge means: this enables to avoid the fragile products from        being damaged by shear effect between the discharge means and        the sides of the cavity.    -   on the other hand, the device comprises a flexible communication        means for the fragile products that extend between the discharge        means and the support; this communication means channels the        fragile products from the orifice of the hopper towards a cavity        located facing said orifice.

According to the characteristics of the invention, which can be takenindividually or in combination:

-   -   the communication means can extend from the periphery of the        discharge means,    -   the communication means can define a volume connecting the        discharge means and the support,    -   the communication means can comprise flexible components        provided to ensure the guiding of the products when they fall in        a cavity located facing the discharge means; in another        embodiment, the communication means is simply a flexible tube,    -   the free end of the flexible components is in contact with the        surface of the support, particularly with the periphery of a        cavity when this cavity is facing the discharge means; the        communication means are therefore provided to sweep the surface        of the support as the latter is in motion, thereby reducing the        shear effect on the fragile products,    -   the flexible components are threads, filaments, hairs or thin        strips,    -   the support can be a sphere rotationally mounted or a cylinder        rotationally mounted about an axis,    -   the at least one cavity can be of a hemispherical shape,    -   the device can comprise an ejection means capable of collecting        the products that have exited a cavity and to guide them towards        the exterior of the device,    -   the device can comprise an enclosure that forms a thermal        barrier, said enclosure enclosing the storage means,    -   the device can further comprise a control means provided        particularly to adjust the speed of motion of the support.

The invention also relates to a vehicle, such as an aircraft, comprisinga device according to the invention.

The invention also relates to a method for dropping insects using adevice according to the invention, comprising steps consisting of:

-   -   Filling the storage means with insects,    -   Activating the support so as to drop the insects.

The method can further comprise a prior step consisting of cooling thestorage means, so as to make or keep the insects lethargic.

It can also comprise a prior step consisting of loading the device intoa vehicle such as an aircraft so as to drop the insects in flight.

Advantageously, the insects are sterilised by irradiation or geneticallymodified so that the offspring thereof is not viable.

Embodiments and different variants are described below, as non-limitingexamples, with reference to the appended drawings, wherein:

FIG. 1 schematically represents a device in elevation,

FIG. 2 represents a magnified view of the catch area of the products,

FIGS. 3A and 3B schematically represent a cross-sectional view ofanother embodiment of the invention.

FIGS. 1 and 2 represent a device 10 for dropping fragile products 5, forexample insects. The device 10 is represented in the operating positionthereof, the notions of top and bottom, lower and upper, willhereinafter be made with reference to this position.

The products 5 are stored in a hopper 4 following the vertical axisZ-Z′, in the operating position, having, such as represented, the shapeof a funnel and comprising a discharge means 4 a in the form of apartially-lower orifice, and a cover 4 b in the upper portion. Thishopper 4 is contained in an enclosure 8, advantageously an enclosureprovided to maintain a setpoint temperature, as will be explained infurther detail below. The orifice 4 a opens onto the lower face 8 a ofthe enclosure, which enables the products to flow from the hopper 4 andout of the enclosure 8.

A cylindrical support 2 is placed at a distance d under the lower face 8a of the enclosure. This cylinder is rotationally mounted about an axisA-A′ orthogonal to the axis Z-Z′ of the hopper. The support could have ashape other than cylindrical; it could for example be spherical.Depending on the intended use, the distance d is between 1 and 3 cm,although it is not limited thereto.

From the lower face 8 a of the enclosure and at the periphery of theorifice 4 a, in the direction of the cylinder 2, extends a set offlexible components (for example threads, filaments, hairs, thin strips,although not limited thereto) forming a brush 3. The components of thebrush 3 form a soft wall defining a volume wherein the products 5present in the hopper 4 can fall by gravity into a cavity of the support2: this volume therefore brings the opening 4 a of the hopper intocommunication with the cavity. The volume can be any kind of shape:cylindrical, conical, etc. This brush 3 is therefore different fromother known brushes, in that it is substantially “hollow” and forms aflexible channel through which the products can flow from the orifice 4a of the hopper 4 towards a cavity 1 a, 1 b, without being dispersed.

Such as represented, the cylinder 2 comprises two cavities 1 a, 1 b atthe surface thereof, the cavity 1 b being concealed by the brush 3. Thecavities 1 a, 1 b can be any shape, but preferably a spherical shape;for a greater volume, they can extend along a generator of the cylinder2. The number of cavities at the surface of the support could bedifferent than two.

The brush 3 has two purposes:

-   -   Thanks to the volume it defines, it guides the fragile products        5 from the orifice 4 a towards a cavity 1 a, 1 b when the cavity        is located facing the orifice 4 a; it thereby prevents the        dispersion of the fragile products between the hopper 4 and the        support 2,    -   It reduces the shear stress applied to the fragile products when        the cylinder 2 rotates, thereby reducing the risk of said        fragile products being damaged.

The length of the components of the brush 3 is such that the free endsof these components are in permanent contact with the surface of thesupport 2 and brush said surface as it rotates. The components of thebrush 3 are not necessarily all of the same length. The free ends ofthese components form a curve that reproduces the shape of theintersection of the volume defined by the brush 3 and the support 2 inorder to guarantee a good seal between the brush 3 and the support 2,and on the other hand, to limit the friction stress on the fragileproducts. Thus, in the event where the brush 3 defines a volume with acylindrical shape with a circular base:

-   -   In the case where the support 2 is a cylinder, the free ends of        the components of the brush 3 form a left curve which is that of        the intersection of both cylinders, and consequently the        components of the brush 3 are not all the same length.    -   In the case where the support 2 is a sphere, the free ends of        the components of the brush 3 form a curve which is that of the        intersection of a cylinder and a sphere, i.e. a circle (insofar        as the axis of the cylinder passes through the centre of the        sphere), in which case the components of the brush 3 are all the        same length.

In addition, the arrangement of these components is such that, when theopening 4 a is located facing a cavity 1 a, 1 b, the free ends thereofsurround the periphery of the cavity, so as to prevent the dispersion offragile products between the brush and the support 2.

When the support 2 continues the rotation thereof, the products 5 whichhad fallen in a cavity 1 a, 1 b are brushed by the brush 3 and canescape from the cavity. In FIG. 2, the support 2 has begun the rotationthereof and the fraction of products 5 a that have fallen in the cavitycan start escaping from it (arrow F).

FIG. 1 represents groups of such products 5 a, collected in an ejectionmeans 7, which, in this case, is shaped like a funnel. The funnelcomprises an output duct 7 a that guides the groups 5 a of productstowards the outside of the device 10. This ejection means 7 and theoutput duct 7 a thereof are advantageous in the case where the device isloaded in a transport means, such as an aircraft, to ensure the productsundergo a “soft” transition between the inside of the device and theoutside. FIG. 1 also represents a group 5 b of such products that haveexited the device 10.

The device 10 thus enables to drop precisely-measured quantities offragile products in the environment without damaging them. It isunderstood that it is easy to adjust the measured quantities by changingthe shape and/or the number of cavities 1 a, 1 b, as well as therotational speed of the support 2. In addition, this rotational speed isnot necessarily constant, it being able to progress step-by-step.

The fragile products to be dropped are for example seeds, biocides,bacterial spores (such as sporulation as toxic protein crystal for theinsects of, for example, Bacillus thuringiensis israelensis (Bti) andBacillus sphaericus (Bs)), but the device is advantageously used todrop, in a precisely calibrated manner, insects that have beensterilised by irradiation or genetically modified to fight certaindiseases such as malaria and arboviruses or African trypanosomiasistransmitted by glossina (tsetse fly). The dropped insects startcompeting with “natural” insects, but do not produce offspring. They canalso be parasitoids.

In this case, it is useful that the insects are maintained at arelatively low temperature, of between 8° C. and 10° C., and thereforelethargic, inside the hopper 4. In this case, the enclosure 8 forms athermal barrier and the device 10 comprises a means to supply cold or,alternately, is suitable for receiving cold bodies such as freezer packsthat change phase at a given temperature and/or dry ice.

The insects do not all have the same fragility, and the components ofthe brush 3 are advantageously adapted to the type of insect to drop.For example, glossina is a relatively resistant fly and the hair or thethreads of the brush 3 can be relatively rigid. In contrast, mosquitoesare fragile and the “hairs” of the brush 3 will have to be a lot softerin order not to injure them. The components of the brush 3 can be chosenfrom among natural fibres (boar bristles, etc.) or artificial fibres.They can also be flexible thin strips. A person skilled in the art willknow how to select the type of fibre or thin strips suitable for anyinsect.

FIGS. 3A and 3B illustrate another embodiment of the device. The entireupstream section of the device is identical to the example of FIGS. 1and 2: hopper 4, enclosure 8, and brush 3. However, in this embodiment,the support is not moved rotationally but by a translational motion andit is made of a plate 20.

In the illustrated example, the plate 20 comprises two transversalcavities 10 a, 10 b. The plate 20 is moved in a back-and-forth motion soas to present facing the orifice 4 a of the hopper 4, sometimes thefirst cavity 10 a, and sometimes the second cavity 10 b. When the cavity10 a is facing the orifice 4 a (FIG. 3A), it is filled with fragileproducts and the second cavity 10 b is emptied. The plate 20 then movestowards the left (arrow F1) to find itself in the position of FIG. 3B,wherein the cavity 10 a is emptying and the cavity 10 b is being filled.Then, the plate 20 returns to the position of FIG. 1 by moving towardsthe right (arrow F2).

For the cavity located facing the orifice 4 a to fill without emptyingat the same time, and to guide the products out of the cavity that is tobe emptied, the plate slides between two fixed guides, an upper guide 11a and a lower guide 11 b. The upper guide 11 a comprises a transversalopening located facing the orifice 4 a, so as to enable the filling ofthe cavity located facing the orifice 4 a, and extends substantially oneither side of this opening. On the contrary, the lower guide 11 bcomprises a full part located facing the orifice 4 a.

In this manner:

-   -   As illustrated in FIG. 3A, the first cavity 10 a is filled with        fragile products, which cannot escape as the cavity is closed in        the lower part thereof by the lower guide 11 b, while the second        cavity 10 b is being emptied, the products being prevented from        escaping from the upper part of the cavity by the right wing of        the guide 11 b,    -   FIG. 3B illustrates the mirror situation, wherein the second        cavity 10 b is being filled with fragile products, which cannot        escape as the cavity is closed in the lower part thereof by the        lower guide 11 b, while the first cavity 10 a is being emptied,        the products being prevented from escaping from the upper part        of the cavity by the left wing of the guide 11 b.

To avoid injuring the fragile products during movements of the drawer ofthe support 20, the periphery of the openings 10 a, 10 b isadvantageously equipped with small brushes 30.

In another version of this embodiment, the support 20 could be circularand rotationally-driven about an axis parallel to the Z-Z′ axis of thehopper.

1. A device (10) for dropping fragile products (5) comprising: a storagemeans (4) of said products, comprising a discharge means (4 a) of saidproducts, a distribution means of the fragile products comprising atleast one cavity (1 a, 1 b, 10 a, 10 b) provided at the surface of asupport (2, 20), the support being capable of taking at least twopositions, a first position wherein the at least one cavity is locatedfacing and at a distance of said discharge means and can be filled withfragile products, and a second position wherein said cavity is spacedapart from said discharge means and can be emptied, wherein said devicecomprises a flexible means of communication (3) of the discharge meanswith at least one cavity in order to fill said cavity with fragileproducts.
 2. The device for dropping fragile products according to claim1, wherein the communication means (3) extends from the periphery of thedischarge means (4 a).
 3. The device for dropping fragile productsaccording to claim 1, wherein the communication means (3) defines avolume connecting the discharge means (4 a) and the support (2).
 4. Thedevice for dropping fragile products according to claim 1, wherein thecommunication means (3) comprises flexible components provided to ensurethe guiding of the products (5) when they fall in a cavity (1 a, 1 b, 10a, 10 b) located facing the discharge means (4 a).
 5. The device fordropping fragile products according to claim 4, wherein the free end ofthe flexible components is in contact with the surface of the support(2), particularly with the periphery of a cavity (1 a, 1 b, 10 a, 10 b)when this cavity is facing the discharge means (4 a).
 6. The device fordropping fragile products according to claim 4, wherein the flexiblecomponents are threads, filaments, hairs or thin strips.
 7. The devicefor dropping fragile products according to claim 1, wherein the support(2) is a sphere rotationally mounted, or a cylinder rotationally mountedabout an axis (A-A′).
 8. The device for dropping fragile productsaccording to claim 1, wherein at least one cavity (1 a, 1 b) is of ahemispherical shape.
 9. The device for dropping fragile productsaccording to claim 1, wherein it comprises an ejection means (7) capableof collect the products (5) that have exited a cavity (1 a, 1 b, 10 a,10 b) and to guide them towards the exterior of the device.
 10. Thedevice for dropping fragile products according to claim 1, wherein itcomprises an enclosure (8) that forms a thermal barrier, said enclosureenclosing the storage means (4).
 11. The device for dropping fragileproducts according to claim 1, wherein it further comprises a controlmeans provided particularly to adjust the speed of motion of the support(2).
 12. A vehicle comprising a device (10) according to claim
 1. 13. Amethod for dropping insects using a device (10) according to claim 1,wherein it comprises the steps consisting of: filling the storage means(4) with insects, A activating the support (2) so as to drop theinsects.
 14. The method for dropping insects according to claim 13,wherein it comprises a prior step consisting of cooling the storagemeans (4) so as to make or keep the insects lethargic.
 15. The methodfor dropping insects according to claim 13, wherein it comprises a priorstep consisting of loading the device into a vehicle such as an aircraftso as to perform the insect drop in flight.
 16. The method for droppinginsects according to claim 13, wherein the insects are sterilised byirradiation or genetically modified so that the offspring thereof is notviable.